Impact assessment of high-power domestic EV charging proliferation of a distribution network

Abstract

Transport electrification is becoming the mainstream as a means to improve efficiency, performance, and sustainability of transportation systems. Electrical vehicles (EVs) can help to de-carbonise the environment, but a downside is the technical issues presented to the low-voltage distribution network. To quantify the stochastic nature of transport-affected electrification, probabilistic load flow is employed. Monte Carlo-based simulation is applied to accommodate the probabilistic uncertainties associated with variable EV charging patterns. This study considers high-power charging (up to 11 kW) at the domestic level while monitoring power quality variations (voltage drop, voltage unbalance factor, voltage sag) standards. This work focuses on the Irish and UK, distribution system operator's–transmission system operator's perspectives, as it will help to identify the likely impacts due to high-EV charger proliferation at household locations. The results indicate that if a 3.68 kW charger is used at the domestic level, it is possible for 40% of total household consumers to connect EVs directly to the distribution network without any power quality breaches. Furthermore, the proliferation of EV can be increased up to 100% if constrained to the start, and middle portions of the network (relative to the feeder substation transformer). For higher charger capacities (up to 11 kW), a bottleneck is presented regarding a resultant voltage unbalance factor.